just remember that \ is the escape character. When found in a string:

\\ = \
\" = "
\n = newline
\r = carriage return
\t = tab
\0 = NULL

True enough, I just don''t know of any systems where (''\0'' != NULL), can anyone point one out, I''m interested now.

quote:Original post by furby100

Original post by JonStelly
\0 = NULL

Technically, \0 is not always the same as NULL. NULL is the value of a pointer which does not point to any memory. \0 is the value of a character which is not defined. They do not have to be the same, although they are on DOS based Intel compatible platforms.



"\0" is not the value of a character which is undefined. "\0" represents the "null character", which has the ASCII code ''0'' (zero). The reason NULL==''\0'' is this: ''\0'' represents a byte (unsigned char) with value 0. NULL represents a pointer (stored as a long) with no value, which is also stored as 0. Hence, 0==0…

"Technically", they''re not the same because one represents a long and one represents an unsigned char, but they have the same value.

Of course, ''0'' has a value of 48 (0x30), it''s ASCII code.

Time to clear some confusion about NULL! According to the ISO C++ standard, NULL is defined as integer 0, but may not be represented in memory as 0. Therefore...

void* a = 0; // a does not point to anything
void* b = NULL; // a == b
void* c = 1; // error (can only convert integer 0 to ptr!)

However... Assigning zero to a pointer merely says you want a pointer that points to nothing. That doesn''t mean that the pointer is represented in memory by a 0. Therefore, the following two statements are not equivalent. (assuming ptr is a void*)

ptr = 0;
memset(&ptr, 0, sizeof(ptr));

Granted, I do not know of a platform where NULL pointers are not represented as 0 (actually, I think NeoTuri in DALnet #programmers said some RISC platform used -1 (0xFFFFFFFF), but I can''t verify that). According to the C++ standard though, it can happen.

AegisKnight
http://www.nerv-un.net/~aegis/